1.zero-based indexing

Just like an ordinary primitive byte array, ByteBuf uses zero-based indexing. It means the index of the first byte is always 0 and the index of the last byte is always capacity - 1. For example, to iterate all bytes of a buffer, you can do the following, regardless of its internal implementation:

ByteBuf buffer = ...;
for (int i = 0; i < buffer.capacity(); i ++) {
     byte b = buffer.getByte(i);
     System.out.println((char) b);
}